10、RestTemplate方式实现远程调用Client
作者：互联网
一、JSONObject类详解：
JSONobject是FastJson提供的对象，在API中是用一个私有的常量map进行封装的，实际就是一个map，只不过 FastJson对其进行了封装，添加了很多方便快捷的属性方法。
添加相关依赖：
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.79</version>
</dependency>
1、将Java对象转化成String：
2、将String类型转json对象，取JSON中KEY对应的VALUE：
3、将String对象转化为List类型：
public class JSONObjectDemo {
public static void main(String[] args) {
//创建对象
List<JsonObjectVO> list = new ArrayList<>();
//对象1
JsonObjectVO vo1 = new JsonObjectVO();
vo1.setUuid(UUID.randomUUID().toString());
vo1.setName("1");
//对象2
JsonObjectVO vo2 = new JsonObjectVO();
vo2.setUuid(UUID.randomUUID().toString());
vo2.setName("2");
list.add(vo1);
list.add(vo2);
ResponseVO responseVO = ResponseVO.builder()
.uuid(UUID.randomUUID().toString())
.list(list)
.build();
/**
* 1、java对象转化成String
* toPrint:{"list":[{"name":"1","uuid":"b73bb9e8-f7a3-4dcf-8d8d-51313c7f5fd7"},{"name":"2","uuid":"ef109d35-cd07-45cd-9b45-791b205c878f"}],"uuid":"dbc3b9c6-2360-4b83-9d15-b88fe7980f27"}
* */
String str = JSONObject.toJSONString(responseVO);
/**
* 2、String类型转json对象，取JSON中的KEY
* toPrint:[{"name":"1","uuid":"b73bb9e8-f7a3-4dcf-8d8d-51313c7f5fd7"},{"name":"2","uuid":"ef109d35-cd07-45cd-9b45-791b205c878f"}]
* */
Object data = JSONObject.parseObject(str).get("list");
/**
* 3、将String对象转化为List类型
* toPrint:[JsonObjectVO(uuid=aebd390d-f543-4410-9c3a-98f2cb057757, name=1), JsonObjectVO(uuid=d170bb12-7570-47dd-8f2d-9ec2df5573c5, name=2)]
* */
List<JsonObjectVO> aList = JSONObject.parseArray(JSONObject.toJSONString(data),JsonObjectVO.class);
System.out.println(str);
System.out.println(data);
System.out.println(aList);
}
}
二、RestTemplate详解：
RestTemplate是由Spring框架提供的一个可调用REST服务的类，它简化了与HTTP服务的通信方式，统一了RESTFUL的标准，封装了HTTP连接。相较于之前常用的HttpClient，RestTemplate是一种更为优雅的调用RESTFul服务的方式。
1、添加依赖：
<!--JSONObject插件-->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.79</version>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
<version>3.1</version>
</dependency>
2、声明RestTemplate配置类：
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;
@Configuration
public class RestTemplateConfig {
@Bean
public RestTemplate restTemplate(){
return new RestTemplate();
}
}
3、自定义远程调用Client通用工具类（重）：
import com.alibaba.fastjson.JSONObject;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpMethod;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Component;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;
import org.springframework.web.client.RestTemplate;
import java.util.HashSet;
import java.util.Map;
import java.util.Optional;
@Slf4j
@Component
public class HttpClientUtil {
@Autowired
private RestTemplate restTemplate;
/**
* @Param basisUrl:根地址(不带请求参数)
* @Param param:请求参数
* @Param method:请求方式(HttpMethod.GET、HttpMethod.POST......)
* @Param authToken:请求令牌
*/
public String getUrlResponse(String basisUrl, Map<Object, Object> param, HttpMethod method, String authToken) {
MultiValueMap heards = new LinkedMultiValueMap();
if (StringUtils.isNotBlank(authToken)) {
heards.add("Authorization", authToken);
}
//合成请求地址
String url = buildUrl(basisUrl, param);
log.info("请求地址为：" + url);
HttpEntity<Object> httpEntity = new HttpEntity<>(heards);
ResponseEntity<Object> response = restTemplate.exchange(url, method, httpEntity, Object.class, param);
String jsonString = JSONObject.toJSONString(response.getBody());
return jsonString;
}
/**
* 拼接url地址:
* 例：http://127.0.0.1:xxx/xx/xxx?xx=xx&xx=xx
*/
private String buildUrl(String basisUrl, Map<Object, Object> param) {
StringBuilder params = new StringBuilder(basisUrl);
params.append("?");
Optional.ofNullable(param.entrySet()).orElse(new HashSet<>()).stream().forEach((Map.Entry entry) -> {
params.append(entry.getKey()).append("=").append(entry.getValue()).append("&");
});
return params.toString().substring(0, params.toString().length() - 1);
}
}
三、远程调用的实现：
1、test-demo工程：
声明控制类：
@RestController
@RequestMapping("/v1")
public class DemoController {
@Autowired
private DemoService demoService;
/**
* get方式
* 查询全量信息
*
* http://localhost:8081/v1/get-detail?pageNum=1&pageSize=8
* */
@GetMapping("/get-detail")
public Response<List<ResponseVO>> list1(
@RequestParam(value = "pageNum", required = false , defaultValue = "1") Integer pageNum,
@RequestParam(value = "pageSize", required = false , defaultValue = "8") Integer pageSize) {
return Response.success(demoService.selectDetail(pageNum , pageSize));
}
/**
* post方式
* 查询全量信息
*
* http://localhost:8081/v1/post-detail
* */
@PostMapping("/post-detail")
public Response<List<ResponseVO>> list2() {
return Response.success(demoService.selectList());
}
}
2、client-demo工程：
（1）、获取test-demo工程接口返回：
@Component
@Slf4j
public class HttpClient {
@Autowired
private HttpClientUtil httpClientUtil;
@Value("${url.v1.clent:http://localhost:8081/v1}")
private String url;
public String getGetMethodURL() {
return url + "/get-detail";
}
public String list() {
//获取根地址
String url = getGetMethodURL();
//放置请求参数
Map<Object, Object> param = new HashMap<>();
param.put("pageNum", 1);
param.put("pageSize", 100);
String jsonString = httpClientUtil.getUrlResponse(url, param, HttpMethod.GET, null);
Object data = JSONObject.parseObject(jsonString).get("entity");
if (ObjectUtils.isEmpty(data)) {
return "数据为空";
}
String dataList = JSONObject.toJSONString(data);
return dataList;
}
}
（2）、业务类：
@Service
public class DemoServiceImpl implements DemoService {
@Autowired
private HttpClient httpClient;
@Override
public String selectList() {
return httpClient.list();
}
}
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<iframe height="240" width="320"></iframe>标签：10,String,RestTemplate,springframework,Client,param,org,import,public 来源： https://www.cnblogs.com/Iven-L/p/16595075.html